National Road I-6 (Bulgarian: Републикански път I-6) is a major road in Southern Bulgaria.

It runs from Gyueshevo at the border with North Macedonia and Burgas on the Black Sea coast.

It descends and bypasses Kyustendil, crosses the Konyavska mountain and then passes through the centre of Radomir.

[1] Road I-6 joins the south and east sides of the Sofia ringroad and then continues south of the Balkan Mountains up to the city of Sliven.

The road then passes through Karnobat and Aytos before turning south-east to reach Burgas, the fourth largest city in Bulgaria situated on the Black Sea coast.